Radiological imaging device with advanced sensors

ABSTRACT

A method and device for acquiring a radiological image of at least part of a patient placed in a gantry. The method includes causing a source to emit radiation that passes through the at least part of the patient and receiving the radiation at a detector. In one embodiment the detector may include at least one first linear sensor having a first sensitive surface and a second linear sensor having a second sensitive surface, wherein the sensitive surfaces are partially overlapped along the direction of movement. The method also includes generating the radiological image at a control unit by generating a first image acquired by the first linear sensor and a second image acquired by the second linear sensor. The control unit may overlap the first and second images in a region where the first and second linear sensors overlap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/366,883, filed Dec. 1, 2016, now U.S. Pat. No. 10,413,265, which is acontinuation of U.S. patent application Ser. No. 14/323,808, filed Jul.3, 2014, now U.S. Pat. No. 9,510,793, and claims priority to U.S.Provisional Patent Application Nos. 61/932,024, filed Jan. 27, 2014;61/932,028, filed Jan. 27, 2014, 61/932,034, filed Jan. 27, 2014; and61/944,956, filed Feb. 26, 2014, the contents of which are incorporatedherein by reference in their entireties.

BACKGROUND 1. Field

Example aspects herein relate generally to obtaining radiologicalimages, and, more particularly, to a method, system, apparatus, andcomputer program for performing a total body scan and reconstructing animage of a patient's entire body or an extensive portion thereof.

2. Description of Related Art

Total body radiological imaging devices comprise a bed on which thepatient is placed; a so-called gantry having a cavity in which theportion to be analyzed is inserted and suitable to perform the imagingof the patient; and a control station suitable to control thefunctioning of the device.

In particular, the gantry comprises a source suitable to emit radiationon command, such as X-rays, and a detector suitable to receive theradiation after it has traversed the patient's body and to send a signalsuitable to permit the visualization of the internal anatomy of thepatient.

Typically, given the need to visualize extensive parts of the body, thedetector used is a flat panel sensor, said flat panel sensor having aparticularly extensive detection surface, which in some cases exceeds1600 cm².

For example, flat panel sensors may be a direct-conversion type, andcomprise a panel suitable to receive X-rays emitted by the source and toproduce a series of electric charges in response, a segmented matrix ofTFT in amorphous silicon which receives the aforementioned electriccharges, and an electronic reading system. Flat panel sensors also maybe an indirect-conversion type, comprising a layer suitable to receiveX-rays emitted by the source and to produce a series of light photons inresponse (e.g., by scintillation), a segmented matrix of photodetectors(e.g. TFT, CMOS, CCD, and the like) that convert the aforementionedlight photons into electric charges, and an electronic reading system.When radiation has struck the entire flat panel sensor, the electronicreading system determines the quantity of electric charge received byeach TFT segment in a direct-conversion flat panel sensor or thequantity of electric charge generated by each photodetector of anindirect-conversion type of flat panel sensor, and correspondinglygenerates a matrix of numbers which represent the digital image.

However, flat panel sensors generally cannot absorb radiationcontinuously, owing to, for example, the particular interaction betweenthe charges and the segmented matrix of TFT in amorphous silicon. Thus,in order to perform a total body scan of a patient's body, imageacquisition of the patient's body is divided into a sequence oftwo-dimensional images, which are then reconstructed into a total bodyscan. In particular, reconstruction may require approximating theportions of the body located on edges between two successive images.Furthermore, other portions of the body may have to be reconstructed byapproximation of a series of images of those portions. As a result, theuse of flat panel sensors in this conventional manner results in poorquality radiological imaging, particularly in the case of total bodyscanning.

Moreover, the quality of conventional total body scans is also reducedas a result of diffused, so-called parasitic radiation, formed by theinteractions between X-rays and matter, which hits the detector and thusdegrades the quality of the image. In order to reduce the incidence ofparasitic radiation, conventional radiological imaging devices are oftenfitted with anti-diffusion grids composed of thin lead plates fixedlyarranged parallel to each other so as to prevent the diffused rays fromreaching the flat panel sensor. However, such grids are only partiallyeffective in remedying the effects of parasitic radiation on imagequality. Furthermore, the use of anti-diffusion grids imposes the use ofa higher dose, thereby possibly increasing the danger of causingillness.

Moreover, conventional radiological imaging devices are characterized byhigh production costs and a highly complex construction.

SUMMARY

Existing limitations associated with the foregoing, as well as otherlimitations, can be overcome by a method for operating a radiologicalimaging device, and by a system, apparatus, and computer program thatoperate in accordance with the method.

In one embodiment, a method for acquiring a radiological image of atleast part of a patient placed in a gantry includes causing a source toemit radiation that passes through the at least part of the patient andreceiving the radiation at a detector. The detector may include at leastone first linear sensor having a first sensitive surface and a secondlinear sensor having a second sensitive surface, wherein the sensitivesurfaces are partially overlapped along the direction of movement. Datasignals may be outputted from the detector to a control unit. The methodalso includes generating the radiological image at the control unit bygenerating a first image acquired by the first linear sensor and asecond image acquired by the second linear sensor. To form theradiological image, the control unit may overlap the first and secondimages in a region where the first and second linear sensors overlap.

The method may also include reducing edge effects by reconstructing theradiological image and excluding a portion of the first image thatoverlaps one or more of the edges of the first linear sensor. Also, themethod may include reducing edge effects by reconstructing theradiological image by excluding a portion of the second image thatoverlaps one or more of the edges of the second linear sensor.

In one embodiment, a radiological imaging device includes a gantrydefining an analysis zone in which at least part of a patient is placed.The device also includes a source suitable to emit radiation that passesthrough the at least part of the patient, the radiation defining acentral axis of propagation and a detector suitable to receive theradiation. In one embodiment, the detector includes at least one firstlinear sensor having a first sensitive surface and a second linearsensor having a second sensitive surface. The first sensitive surface issubstantially equal in size to the second sensitive surface, and inrelation to a direction of movement that is perpendicular to the centralaxis of propagation, the first sensitive surface overlaps the secondsensitive surface so that a fraction of the first and second sensitivesurfaces to be hit by the radiation is less than 30%. In otherembodiments, the first sensitive surface overlaps the second sensitivesurface so that a fraction of the first and second sensitive surfaces tobe hit by the radiation is less than 20%. Still in other embodiments,the first sensitive surface overlaps the second sensitive surface sothat a fraction of the first and second sensitive surfaces to be hit bythe radiation is less than 10%.

In one example embodiment herein, a radiological imaging devicecomprises a gantry defining an analysis zone in which at least part of apatient is placed, a source suitable to emit radiation that passesthrough the at least part of the patient, the radiation defining acentral axis of propagation, a detector suitable to receive theradiation, a translation mechanism adapted to translate the source andthe detector in a direction of movement substantially perpendicular tothe central axis of propagation, and a control unit. The control unit isadapted to acquire an image from data signals received continuously fromthe detector while the translation mechanism continuously translates thesource emitting the radiation and the detector receiving the radiation,so as to scan the at least part of the patient.

In another example embodiment herein, the detector includes at least onefirst linear sensor having a first sensitive surface and a second linearsensor having a second sensitive surface, wherein the sensitive surfacesare partially overlapping along the direction of movement. In someexample embodiments herein, a superimposition zone corresponding to theoverlapping of the sensitive surfaces is positioned substantially at thecentral axis of propagation.

In some example embodiments herein, the detector includes an inversionunit adapted to rotate at least one of the first linear sensor and thesecond linear sensor. In a further example embodiment herein, theinversion unit rotates the at least one of the first linear sensor andthe second linear sensor in relation to an axis of rotationsubstantially parallel to the central axis of propagation.

In yet another example embodiment herein, the detector includes at leastone flat panel sensor having a radiation sensitive surface and operablein at least a flat panel mode and a linear sensor mode.

In an example embodiment herein, the radiological imaging device furthercomprises a bed suitable to support the patient and defining an axis ofextension. Furthermore, in another example embodiment herein, thedirection of movement is substantially parallel to the axis of extensiondefined by the bed.

In an example embodiment herein, the translation mechanism includes alinear guide.

In yet another example embodiment herein, the radiological imagingdevice further comprises a rotation mechanism adapted to rotate thesource and the detector in relation to the axis of extension. In afurther example embodiment herein, the rotation mechanism includes apermanent magnet rotor connected to the source and to the detector.

In an example embodiment herein, the radiological imaging device furthercomprises a bed suitable to support the patient and defining an axis ofextension; a rotation mechanism adapted to rotate the source and thedetector in relation to the axis of extension; and at least onepositioning laser mounted on the gantry that projects a positioningguidance marker onto the patient; wherein the control unit is adapted toconfigure, based on received information, at least one of an energy ofthe radiation and a radiation filter arranged to absorb at least aportion of the radiation before the radiation passes through the atleast part of the patient, and wherein the detector includes at leastone flat panel sensor having a radiation sensitive surface and operablein at least a flat panel mode and a linear sensor mode.

The radiological imaging device can be useful for performing highquality total body scans with a reduced dosage of radiation. Theradiological imaging device also can be constructed with reducedproduction costs and reduced complexity.

Further features and advantages, as well as the structure and operationof various embodiments herein, are described in detail below withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

The characteristics of the example embodiments herein are clearlyevident from the detailed descriptions thereof, with reference to theaccompanying drawings.

FIG. 1 illustrates a radiological imaging device.

FIG. 2a illustrates a cross-section of an example embodiment of theradiological imaging device of FIG. 1.

FIG. 2b is a table showing predetermined relationships for configuringan X-ray source according to an example embodiment herein.

FIG. 2c depicts a source subassembly of the imaging device of FIG. 1according to an example embodiment herein.

FIGS. 3a and 3b illustrate a detector subassembly of the imaging deviceof FIG. 1 according to an example embodiment herein.

FIG. 4 illustrates images acquired by the detector subassembly of FIGS.3a and 3 b.

FIG. 5a illustrates a matrix mode of a flat panel sensor subassembly ofthe imaging device of FIG. 1 according to another example embodimentherein.

FIG. 5b illustrates a linear sensor mode of a flat panel sensorsubassembly of the imaging device of FIG. 1 according to another exampleembodiment herein.

FIG. 6a illustrates a gantry subassembly, with a cut-away portion,according to an example embodiment of the radiological imaging device ofFIG. 1.

FIG. 6b illustrates a perspective view of the gantry subassembly shownin FIG. 6 a.

FIG. 7 is a flowchart illustrating an imaging procedure according to anexample embodiment herein.

FIG. 8 illustrates a block diagram of an example computer system of theradiological imaging system shown in FIG. 1.

DETAILED DESCRIPTION

With reference to said drawings, reference numeral 1 globally denotes aradiological imaging device. In particular, the radiological imagingdevice 1 is useful in the medical/veterinary sphere to perform a graphicreconstruction of at least a portion of a patient's body. In one exampleembodiment herein, the radiological imaging device 1 is suitable toperform a total body scan, that is to say a graphic reconstruction ofthe whole body or of an extensive portion thereof.

FIG. 1 illustrates an example embodiment of the radiological imagingdevice 1. The radiological imaging device 1 comprises a bed 20 suitableto support the patient in the correct position and defining a preferreddirection of extension 20 a; a gantry 30 defining an analysis zone 30 ain which at least part of the portion of the patient's body to be imagedis placed and defining a prevailing direction of development,preferably, substantially parallel to the direction 20 a; a load-bearingstructure 40 suitable to support the bed 20 by way of columns 52 andalso suitable to support the gantry 30; a control unit 70 suitable to beplaced in data transfer connection with the various components of theradiological imaging device 1; a translation mechanism 50 suitable tomove the gantry 30 in a direction of movement 50 a; and a rotationmechanism 60 (shown in FIG. 2a ) suitable to rotate the gantry 30 aroundthe direction of extension 20 a. In one example embodiment, the controlunit 70 is mounted to the gantry 30 (as shown in FIGS. 1, 6 a, and 6 b),although in other examples it can be housed in a stand-alone unit (notshown) such as, for example, a workstation cart, or may formed ofmultiple parts, such as a first part mounted to the gantry 30 and asecond part housed in a stand-alone unit (not shown). These examples aremerely illustrative in nature, and in other embodiments, the controlunit 70 can be located at other positions and locations besides thosedescribed above.

The gantry 30 further comprises a source 31 (FIG. 2a ) suitable to emit,in the analysis zone 30 a, radiation defining a central axis ofpropagation 31 a; a detector 32 facing the analysis zone 30 a so as toreceive the radiation after it has traversed the patient's body; and ahousing 33 at least partially containing the source 31 and the detector32. Additionally, in a further example embodiment herein, the gantry 30further comprises a laser positioning system that includes at least onehorizontal laser 72 and at least one vertical laser 74 (FIGS. 6a and 6b). The foregoing subcomponents of the gantry will now be described inturn.

The source 31 is suitable to emit, in a known manner, radiation capableof traversing the body of the patient and interacting with the tissuesand fluids present inside said patient. In one example embodimentherein, the source 31 emits, under control of the control unit 70,ionizing radiation, and more particularly, X-rays defining a centralaxis of propagation 31 a.

FIG. 2c depicts the source 31 of the radiological imaging device 1 ofFIG. 1, according to an example embodiment herein. As represented inFIG. 2a and shown in FIG. 2c , in one example embodiment herein, anX-ray filter 76 can optionally be positioned in front of the source 31,as represented in FIG. 2a and shown in FIG. 2c , and function to modifythe energy distribution of the radiation emitted by the source 31 alongthe axis of propagation 31 a (e.g., by absorbing low power X-rays) priorto the X-rays traversing the patient (although source 21 also may beoperated without an X-ray filter 76). The X-ray filter 76 may comprisean aluminum and/or copper sheet (or any other material suitable for theabsorption of radiation) of predetermined thickness.

In another example embodiment herein, a plurality of X-ray filters (notshown) are stored at different locations in the gantry 30, each of theplurality of X-ray filters differing from others of the filters in termsof at least one of a type of material (such as an aluminum and/or coppersheet) or thickness. The control unit 70 can cause a motorized mechanism(not shown) provided within the gantry 30 to retrieve a selected X-rayfilter (e.g., selected by control unit 70 in a manner to be describedfurther herein below) from storage and position the selected X-rayfilter in front of the source 31.

In a further example embodiment herein, the operator can operate controlunit 70 to input information, such as, for example and withoutlimitation, a type of the imaging procedure selected to be performed(e.g., fluoroscopy, tomography, or radiography), a type of patientspecies, the patient's weight, and/or tissue type to be imaged, andcause the control unit 70 to automatically configure the radiologicalimaging device 1 to use an optimal radiation dosage. In response, thecontrol unit 70 determines an X-ray emission energy from the source 31(X-ray emission energy being a function of parameters including X-raytube voltage, X-ray tube current, and exposure time) and/or a type ofX-ray filter 76 to employ, so that the radiological imaging device 1 canperform the selected imaging procedure with an X-ray dosage that is safefor the patient, as well as the operator, while maintaining optimalimage quality.

For example, the control unit 70 can perform the aforementioneddetermination of X-ray emission energy and/or select an X-ray filtertype based on predetermined relationships (e.g., defined in accordancewith look-up table(s), conditional statement algorithm(s), and/ormathematical formula(s) implemented on control unit 70, although theseexamples are not limiting) between the patient information, theradiological imaging procedure selected to be performed, the X-rayemission energy, and the materials and thicknesses of the X-ray filtersavailable in the plurality of X-ray filters located inside the gantry.Examples of such predetermined relationships are shown in the table ofFIG. 2 b.

As but one non-limiting example, if an operator specifies as input (byway of control unit 70) that high resolution tomography is to beperformed on hard tissues (e.g., a thorax region), the control unit 70determines, via a look up table, for example, that the aforementionedinput correlates to operating parameters for the source 31 of 100 kV and60 mA for 5 ms and an X-ray filter 76 of a type comprising a 3 mm thicksheet of aluminum together with a 0.2 mm thick sheet of copper (see FIG.2b ). As another example, if an operator specifies (by way of thecontrol unit 70) that high resolution tomography is to be performed onsoft tissues (e.g., an abdominal region), the control unit 70determines, via a look-up table, for example, that that input correlatesto operating parameters for the source 31 of 60 kV and 60 mA for 10 msand an X-ray filter 76 of a type comprising a 2 mm thick sheet ofaluminum (see FIG. 2b ).

In yet another example embodiment herein, the source 31 is selectablyconfigured (e.g., by control unit 70) to emit either a cone-shaped beamof radiation or a fan-shaped beam of radiation, by configuring the shapeof an adjustable diaphragm 78. The adjustable diaphragm 78, shown inFIG. 2c , comprises at least two movable plates 78 a and 78 b capable ofsubstantially blocking radiation, the plates 78 a and 78 b being movableinto at least one of an open configuration or a slit configuration by amotorized mechanism (not shown) under operator control by way of controlunit 70. When the adjustable diaphragm 78 is configured in the openconfiguration, radiation from the source 31 is not blocked and emitsalong the axis of propagation 31 a in the shape of a cone. When theadjustable diaphragm 78 is configured as a slit, a portion of theradiation of the source 31 is blocked, and thus radiation emits alongthe axis of propagation 31 a in the shape of a fan (i.e., across-section of the cone-shaped radiation) oriented perpendicularly tothe direction of extension 20 a. Thus, in one example embodiment herein,an operator may configure the source 31 to emit either a cone-shapedbeam or a fan-shaped beam by virtue of the adjustable diaphragm 78, andperform different types of imaging with the radiological imaging device1, such as, for example, cone beam tomography or fan beam tomography,respectively.

The laser positioning system (including horizontal laser(s) 72 andvertical laser(s) 74 mounted in the gantry 30), when activated on thecontrol unit 70, projects visual markers onto the patient in order tofacilitate positioning of the patient on the bed 20, and moreparticularly, within the analysis zone 30 a. In particular, in oneexample embodiment herein, the laser positioning system is used inconjunction with an adjustable bed (serving as bed 20), according to oneor more of the example embodiments described in U.S. Provisional PatentApplication Nos. 61/932,034 and 61/944,956, which are incorporated byreference herein in their entireties, as if set forth fully herein.Referring to FIGS. 6a and 6b , which illustrate a gantry 20 according toan example embodiment of the radiological imaging device illustrated inFIG. 1, the laser positioning system includes at least one horizontallaser 72, which projects horizontal visual markers 73 to aid theoperator in adjusting the height and inclination of the patient withrespect to the gantry 30, and/or at least one vertical laser 74, whichprojects a top-down marker 75 to aid the operator in adjusting thelateral centering of the patient with respect to the gantry 30. Theoperator adjusts the position of the patient by observing the positionof the patient with respect to the projected laser markers 73 and 75,and thus with respect to the analysis zone 30 a, and then, for example,manually repositioning the patient on the bed 20 or by adjustingcontrols on the aforementioned adjustable bed (not shown in FIGS. 6a and6b ) until the patient is deemed by the operator to be in the correctposition for imaging.

Referring again to FIG. 2a , the detector 32 will now be described. Thedetector 32 is suitable for detecting radiation emitted by source 31and, in response thereto, outputting corresponding data signals to thecontrol unit 70 at a particular frame rate. The control unit 70, inturn, processes the data signals to acquire images. As will be describedfurther herein below, the detector 32 may include either at least onelinear sensor (e.g., such as two linear sensors, as illustrated in FIGS.3a and 3b ) or at least one flat panel sensor capable of operating in alinear sensor mode (FIGS. 5a and 5b ).

In one example embodiment herein, the detector 32 comprises at least onelinear sensor defining a sensitive surface (not shown), that is to say,a surface suitable to detect the radiation emitted by the source 31.

In another example embodiment herein, and with reference to FIGS. 2a,3a, and 3b , the detector 32 comprises at least a first linear sensor 32a defining a first sensitive surface 32 b, and a second linear sensor 32c defining a second sensitive surface 32 d. The sensitive surfaces 32 band 32 d are suitable for detecting radiation emitted by the source 31.In one example embodiment herein, the second sensitive surface 32 d issubstantially coplanar with the first sensitive surface 32 b, althoughthis example is non-limiting. Preferably, the linear sensors 32 a and 32c have a frame rate of, for example, approximately 50 frames per secondto approximately 300 frames per second.

As shown in FIGS. 3a and 3b , the sensors 32 a and 32 c are positionedin such a way as to be in contact with each other and to present thesensitive surfaces 32 b and 32 d substantially perpendicularly to thecentral axis of propagation 31 a. More precisely, they are positioned sothat at least a portion of the first sensitive surface 32 b and at leasta portion of the second sensitive surface 32 d overlap in the directionof movement 50 a, so that when the translation mechanism 50 moves thedetector 32 along said movement direction 50 a, the radiation traversinga defined portion of body hits such portions of the sensitive surfaces32 b and 32 d sequentially and substantially without interruption (thatis to say, in such a way that the radiation passes practically directlyfrom the portion of the first surface 32 b to that of the second 32 d).The aforementioned overlapping portions of the sensitive surfaces 32 band 32 d are positioned substantially at the axis of propagation 31 a.

In particular, the linear sensors 32 a and 32 c have sensitive surfaces32 b and 32 d substantially equal to each other in size and are, inrelation to the direction of movement 50 a, overlapping so that thefraction of the sensitive surfaces 32 b and 32 d suitable to besequentially hit by the radiation as the gantry 30 is moved bytranslation mechanism 50 is substantially less than 30% andparticularly, substantially less than 20%, and more particularly,substantially less than 10%.

A high quality image can be generated from two separate linear sensors32 a and 32 c by virtue of their overlap, as will now be described, byway of example, with reference to FIG. 4. FIG. 4 illustrates arepresentation of a first image “A” acquired by the first sensor 32 aand a second image “B” acquired by the second sensor 32 c. The images“A” and “B” partially overlap in a region “AB” where the first andsecond sensors 32 a and 32 c overlap.

Edge effects that may cause image degradation in corresponding edgeregions of acquired images are minimized by virtue of reconstructing asingle image from the overlapping images “A” and “B” according to anexample embodiment herein. For example, the control unit 70 canreconstruct an image by combining portions of images “A” and “B”,including a portion of image “A” that overlaps an edge of sensor 32 cand a portion of image “B” that overlaps an edge of sensor 32 a, butexcluding a portion of image “B” that corresponds to the edge of sensor32 c and portion of image “A” that corresponds to the edge of sensor 32a (i.e., excluding those portions where images “A” and “B” may manifestundesirable edge effects of the first and second sensors 32 a and 32 c,respectively). Accordingly, the radiological image device 1 is capableof reconstructing an image from two linear sensors while minimizing edgeeffects or other reconstruction errors resulting from the edges of thesensors 32 a and 32 c in the overlapping region, and high quality scansof a patient's body can be obtained, including areas of radiologicalinterest in the patient's body scanned in the overlapping region.

Referring again to FIGS. 2a, 3a, and 3b , the example embodiment ofdetector 32 using linear sensors 32 a and 32 c also can comprise aninversion unit 32 e suitable to rotate at least one of the linearsensors 32 a and 32 c about a substantially non-perpendicular axis ofrotation and, specifically, about an axis substantially parallel to thecentral axis of propagation 31 a, so as to invert the direction ofreading. In particular, the inversion unit 32 e simultaneously rotatesboth sensors 32 a and 32 c substantially in relation to the central axisof propagation 31 a, for example, by an angle substantially equal to180° so as to invert the order of the linear sensors 32 a and 32 c inrelation to the direction of movement 50 a as shown in FIGS. 3a and 3 b.

Alternatively, the inversion unit 32 e can move the sensors 32 a and 32c independently of each other. In particular, the inversion unit 32 emoves the first linear sensor 32 a by means of a roto-translationalmovement, that is, more precisely, a translational movement along adirection of movement 50 a, and a rotational movement about an axis ofrotation parallel to the central axis 31 a of an angle substantiallyequal to 180°. Practically simultaneously to said roto-translationalmovement of the first linear sensor 32 a, the inversion unit 32 erotates the second linear sensor 32 c about an axis of rotation separatefrom the axis of rotation of the first linear sensor 32 a andsubstantially parallel to the axis 31 a. Alternatively, the inversionunit 32 e roto-translates the second linear sensor 32 c along an axissubstantially parallel to the axis of the roto-translation of the firstlinear sensor 32 a.

Another example embodiment of the detector 32 will now be described. Inthis embodiment, the detector 32 comprises at least one flat panelsensor 32 f (as shown in FIGS. 5a and 5b ), that includes an array ofpixels and is capable of operating in a selected one of multipleindependent read-out modes, selectable by control unit 70, including atleast a matrix mode (FIG. 5a ) and a linear sensor mode (FIG. 5b ).

In the matrix mode (FIG. 5a ), the flat panel sensor 32 f outputs, tocontrol unit 70, signals corresponding to radiation detected by pixelsin a region of sensitive surface 32 g. In one example embodiment herein,the sensitive surface 32 g is substantially coextensive with the entirearray of pixels of the flat panel sensor 32 f.

In the linear sensor mode (FIG. 5b ), the flat panel sensor 32 foutputs, to control unit 70, signals corresponding to radiation detectedby the subset of pixels in a region of sensitive surface 32 h. Thesensitive surface 32 h functions effectively as a linear sensor (e.g.,in a manner similar to linear sensors 32 a and 32 c); that is, in oneexample, the sensitive surface 32 h has a frame rate in the range ofapproximately 50 frames per second to approximately 300 frames persecond and has a width that is substantially greater than its length,its length being defined in a direction substantially parallel todirection 50 a and its width being defined substantially perpendicularto the direction of movement 50 a and the central axis of propagation 31a.

The pixel array size of sensitive surfaces 32 g and 32 h can bepredefined for the flat panel sensor 32 f in hardware, firmware,software, or other means by which the flat panel sensor 32 f may becontrolled.

In particular, in one example embodiment herein, the flat panel sensor32 f may be a Hamamatsu model C11701DK-40 flat panel sensor, which canoperate in a matrix mode that provides a sensitive surface 32 g, havinga 1096×888 array of pixels or a 2192×1776 array of pixels, and can alsoseparately operate in a linear sensor mode that provides a sensitivesurface 32 h, having a 1816×60 array of pixels.

Additionally, the flat panel sensor 32 f can be mounted on a panelmotion system 35 that includes guides 34 and a motorized translationmechanism 36 (FIGS. 5a and 5b ). The panel motion system 35 is suitablefor moving the flat panel sensor 32 f along an axis 38, which issubstantially perpendicular to both the gantry direction of movement 50a and the central axis of propagation 31 a. In particular, the axis 38is also parallel to the width of the sensitive surface 32 h when theflat panel sensor 32 f is operating in the linear sensor mode.Accordingly, owing to the panel motion system 35, the flat panel sensor32 f can be operated to acquire a plurality of scans, each at differentbut overlapping locations along the axis 38 (although this example isnon-limiting), as will be described further herein below with referenceto the procedures described in FIG. 7.

Having described various example embodiments of the detector 32, thetranslation mechanism 50 and rotation mechanism 60 of the radiologicalimaging device 1 will now be discussed, with reference to FIG. 1.

The translation mechanism 50 is suitable to translate, at the same time,at least the detector 32 and the source 31 and, in particular, theentire gantry 30, in relation to the load-bearing structure 40 along thedirection of movement 50 a, so as to permit the radiological imagingdevice 1 to perform radiological imaging over practically the entireextension of the bed 20 and therefore the patient. In particular, thedirection of movement 50 a is substantially perpendicular to the centralaxis of propagation 31 a, and more particularly, substantially parallelto the preferred direction of extension 20 a. The translation mechanism50 comprises a linear guide 51 positioned between the gantry 30 and theload-bearing structure 40 and a carriage 53, attached to the gantry 30,suitable to slide along the linear guide 51. In an example embodimentherein, the linear guide 51 may be a motorized linear guide or, morespecifically, an electric motorized linear guide. Preferably, thetranslation mechanism 50 is able to move the gantry 30 and, therefore,the detector 32 and the source 31, at a speed, for example, in the rangeof approximately 2.5 meters per second to approximately 100 meters persecond. Additionally, the translation of the gantry 30 by thetranslation mechanism 50 can be controlled by the control unit 70.

In addition to the translation mechanism 50, the radiological imagingdevice 1 comprises a rotation mechanism 60 (FIG. 2a ) suitable to rotatethe source 31 and the detector 32 with respect to an axis substantiallyparallel to the direction of movement 50 a and, in detail, substantiallycoincident to said preferred direction of extension 20 a. The rotationmechanism 60 is housed inside the gantry 30 and, in particular, insidethe housing 33 so as to rotate the source 31 and the detector 32 inrelation to said housing 33. In one example embodiment, the rotationmechanism 60 comprises a rotor 61, such as a permanent magnet rotor, towhich the source 31 and the detector 32 are connected; and a stator 62integrally connected to the housing 33 and suitable to emit a magneticfield controlling the rotation of the rotor 61, and thereby, of thesource 31 and the detector 32. Operation of the rotation mechanism 60can be controlled by control unit 70.

FIG. 8 illustrates a block diagram of a computer system 80. In oneexample embodiment herein, at least some components of the computersystem 80 can form or be included in the aforementioned control unit 70,and computer system 80 is electrically connected to other components ofthe radiological imaging device 1 (such as, for example, the source 31,the detector 32, the gantry 30, and any subcomponents thereof) by way ofcommunications interface 98 (mentioned below). The computer system 80includes at least one computer processor 82 (also referred to as a“controller”). The computer processor 82 may include, for example, acentral processing unit, a multiple processing unit, anapplication-specific integrated circuit (“ASIC”), a field programmablegate array (“FPGA”), or the like. The processor 82 is connected to acommunication infrastructure 84 (e.g., a communications bus, across-over bar device, or a network). Although various embodiments aredescribed herein in terms of this exemplary computer system 80, afterreading this description, it will become apparent to a person skilled inthe relevant art(s) how to implement the invention using other computersystems and/or architectures.

The computer system 80 may also include a display unit 86 for displayingvideo graphics, text, and other data provided from the communicationinfrastructure 84. In one example embodiment herein, the display unit 86can form or be included in the control unit 70.

The computer system 80 also includes an input unit 88 that can be usedby the operator to send information to the computer processor 82. Forexample, the input unit 88 can include a keyboard device and/or a mousedevice or other input device(s). In one example, the display unit 86,the input unit 88, and the computer processor 82 can collectively form auser interface.

In an example embodiment that includes a touch screen, for example, theinput unit 88 and the display unit 86 can be combined. In such anembodiment, an operator touching the display unit 86 can causecorresponding signals to be sent from the display unit 86 to a processorsuch as processor 82, for example.

In addition, the computer system 80 includes a main memory 90, whichpreferably is a random access memory (“RAM”), and also may include asecondary memory 92. The secondary memory 92 can include, for example, ahard disk drive 94 and/or a removable storage drive 96 (e.g., a floppydisk drive, a magnetic tape drive, an optical disk drive, a flash memorydrive, and the like) capable of reading from and writing to acorresponding removable storage medium, in a known manner. The removablestorage medium can be a non-transitory computer-readable storage mediumstoring computer-executable software instructions and/or data.

The computer system 80 also can include a communications interface 98(such as, for example, a modem, a network interface (e.g., an Ethernetcard), a communications port (e.g., a Universal Serial Bus (“USB”) portor a FireWire® port), and the like) that enables software and data to betransferred between the computer system 80 and external devices. Forexample, the communications interface 98 may be used to transfersoftware or data between the computer system 80 and a remote server orcloud-based storage (not shown). Additionally, the communicationinterface 98 may be used to transfer data and commands between thecomputer system 80 (serving as control unit 70) to other components ofthe radiological imaging device 1 (such as, for example, the source 31,the detector 32, the gantry 30, and any subcomponents thereof).

One or more computer programs (also referred to as computer controllogic) are stored in the main memory 90 and/or the secondary memory 92(i.e., the removable-storage drive 96 and/or the hard disk drive 94).The computer programs also can be loaded into the computer system 80 viathe communications interface 98. The computer programs includecomputer-executable instructions which, when executed by thecontroller/computer processor 82, cause the computer system 80 toperform the procedures described herein and shown in at least FIG. 7,for example. Accordingly, the computer programs can control the controlunit 70 and other components (e.g., the source 31, the detector 32, thegantry 30, and any subcomponents thereof) of the radiological imagingdevice 1.

A procedure for imaging at least a portion of a patient using theradiological imaging device that was described above in a structuralsense, will now be further described in conjunction with FIG. 7. Theprocess starts in Step S702.

Initially, in Step S704, the operator places the patient on the bed 20.In one example embodiment herein, the operator activates the laserpositioning system (comprising lasers 72 and 74, as shown in FIGS. 6aand 6b ), which projects horizontal visual markers 73 to assist theoperator in adjusting the height and inclination of the patient withrespect to the gantry 30, and/or projects a top-down marker 75 to assistthe operator in laterally adjusting the patient with respect to thegantry 30.

Also in Step S704, the operator operates the control unit 70 to specifyimaging parameters, such as the portion of body on which to perform atotal body scan (also referred to as the zone to be imaged) and, inparticular, the inclination of the central axis of propagation 31 a andthe travel of the gantry 30, that is to say the advancement of thegantry 30 along the preferred direction of extension 20 a. The operatoralso may operate the control unit 70 to input patient information (e.g.,species, weight, and/or tissue type to be imaged), and may furthercommand the control unit 70 to automatically configure the radiologicalimaging device 1 to select an appropriate radiation dose based on thepatient information, in the above described manner.

Then, in Step S706, the control unit 70 responds to the aforementionedoperator specified imaging parameters and controls the rotationmechanism 60 so as to rotate the source 31 and the detector 32 in orderto orient the central axis of propagation 31 a in relation to the bed20, and therefore to the patient. Additionally, if the operatorcommanded the control unit 70 to automatically configure theradiological imaging device 1 to use an appropriate radiation dose inStep S704, the control unit 70 configures the X-ray source 31 and theX-ray filter 76 in the manner described above, so as to be prepared toprovide such a dosage. Once the central axis of propagation has reachedthe desired inclination, scanning commences in Step S708.

Step S708 will now be described. During scanning in Step S708, thetranslation mechanism 50 moves the gantry 30 along the preferreddirection of extension 20 a so that the source 31 and the detector 32translate together in relation to the bed 20 and to the patient, therebypermitting the radiation to scan the entire zone to be imaged.Simultaneously to the aforementioned translation action, the source 31emits radiation, which, after traversing the patient's body, is detectedby the detector 32, which in turn sends a suitable signal to the controlunit 70.

The manner in which Step S708 is performed in a case where the detector32 comprises two linear sensors 32 a and 32 c will now be described. Asthe gantry 30 advances in the direction of movement 50 a, the source 31emits radiation, which, after traversing the patient's body, hits thefirst sensitive surface 32 b and, practically simultaneously, hits thesecond sensitive surface 32 d. More particularly, each part of theportion of the body being scanned is first scanned by the portion of thefirst surface 32 b corresponding to the first sensor 32 a part incontact with the second sensor 32 c, and subsequently, is scanned by theportion of the second surface 32 d adjacent to the previous portion. Thelinear sensors 32 a and 32 c detect the radiation and send a continuoussignal to the control unit 70, which thus receives a single signal forthe zone to be imaged and processes the signal to acquire an image ofthe scanned part of the patient.

In some situations, the operator may have selected, in Step S704, adirection of translation of the gantry 30 for imaging that is a reversedirection relative to the orientation of the sensors 32 a and 32 c,which may result in the data output order of the sensors 32 a and 32 cbeing reversed. That is, as the radiological imaging device 1 istranslated and the source 31 is controlled to emit radiation, radiationis first detected by the second sensor 32 c before being detected by thefirst sensor 32 a (see, for example, FIG. 3b ). In order to acquire thedata output in a non-reverse order, in a further example embodimentherein, performing Step S708 using the linear sensors 32 a and 32 c alsomay include a preliminary substep (i.e., that is performed prior to theabove-described scanning in Step S708) of controlling the inversion unit32 e, either manually by the operator or automatically by the controlunit 70, so as to rotate the sensors 32 a and 32 c about an anglesubstantially equal to 180° in relation to the central axis ofpropagation 31 a. By virtue of the preliminary substep, the order of thesensors 32 a and 32 c can be inverted in relation to the direction ofmovement 50 a so that radiation would first be detected by the firstsensor 32 a prior to being detected by the second sensor 32 c (see, forexample, FIG. 3a in comparison to FIG. 3b ).

Having described scanning in Step S708 using the linear sensors 32 a and32 c, scanning in Step S708 in the case where the detector 32 comprisesa flat panel sensor 32 f (versus sensors 32 a and 32 c) operating in alinear sensor mode with sensitive surface 32 h (FIG. 5b ) will now bedescribed.

During a scan, the source 31 continuously emits radiation, whichtraverses the patient's body and hits the sensitive surface 32 h of flatpanel sensor 32 f. As the gantry 30 advances in the direction ofmovement 50 a, the flat panel sensor 32 f detects radiation during suchmovement and sends corresponding signals to the control unit 70.Accordingly, the control unit 70 receives a signal for the entire zoneto be imaged and processes the signal to acquire an image of the scannedpart of the patient.

Additionally, if desired by the operator, one or more additional scansmay be performed. For each additional scan, the flat panel sensor 32 fcan be translated along axis 38 by the panel motion system 35 (undercontrol of control unit 70) to a new position that partially overlapsthe position of the flat panel sensor 32 f in a previous scan, and moreparticularly, the immediately preceding scan. Then, a further scanningprocedure is performed in the manner described above, that is, thegantry 30 advances in the direction of movement 50 a while the source 31emits radiation and the flat panel sensor 32 f continuously outputs asignal to the control unit 70. In this manner, a plurality of scans canbe acquired, each scan being as wide as the sensitive surface 32 h andas long as the travel of gantry 30 along the direction of movement 50 a.The plurality of scans is then provided to the control unit 70 forgraphic reconstruction in Step S710.

Next, in Step S710, the control unit 70 carries out the graphicreconstruction of the zone being imaged using the readings performed bythe detector 32. In the example embodiment where detector 32 comprisestwo linear sensors 32 a and 32 c, overlapping images from first andsecond detectors 32 a and 32 c are reconstructed in the manner describedabove, with reference to FIG. 4.

In the example embodiment where detector 32 comprises flat panel sensor32 f operating in the linear sensor mode, the plurality of scansacquired in Step S708 by flat panel sensor 32 f operating in the linearsensor mode can be reconstructed into one overall image in a manner thatminimizes edge effects in overlapping regions of the plurality ofimages, similar to the manner of reconstruction discussed above withrespect to the two linear sensors 32 a and 32 c (see FIG. 4). Thus, byvirtue of the panel motion system 35, the flat panel sensor 32 f canprovide an overall radiological image that is wider than the sensitivesurface 32 h.

The process ends at step S712. The operator may repeat the process or aportion thereof to acquire additional scans, as desired.

In view of the foregoing description, it can be appreciated that atleast some example embodiments described herein provide a radiologicalimaging device 1 that produces high quality total body scan images.

In fact, the use of the linear sensors 32 a and 32 c or the flat panelsensor 32 f functioning as a linear sensor, together with thetranslation mechanism 50, makes it possible to perform continuous dataacquisition and, consequently, to innovatively obtain a reconstructionbased on a continuous scan of the portion of the body analyzed, ratherthan by the approximation from a number of discrete two-dimensionalimages, as is the case with the prior art radiological imaging devices.

Additionally, by virtue of the partial superimposition of the linearsensors 32 a and 32 c in the example embodiment of detector 32 usingthose sensors, it is possible to obtain a low cost detector 32 with aconsiderably extensive effective sensitive surface, being defined by thecombination of the surfaces 32 b and 32 d. Similarly, in the exampleembodiment of detector 32 employing the flat panel sensor 32 f, byvirtue of mounting the flat panel sensor 32 f on the panel motion system35, it is possible to capture high quality images that are larger thanthe flat panel sensor 32 f.

Furthermore, the radiological imaging device 1 exposes the patient andoperator to a reduced dosage relative to the case of prior art systems.In particular, the use of the linear sensors 32 a and 32 c or the flatpanel sensor 32 f functioning as a linear sensor makes it possible tonot use the anti-diffusion grids and thereby, to reduce the necessaryintensity of the radiation emitted by the source 31.

According to at least some example embodiments herein, the radiologicalimaging device makes it possible to further limit the patient's exposureto radiation. As described above, total body imaging with a flat panelsensor that conventionally has to overlap a number of two-dimensionalimages may irradiate some parts of the body twice or more. As a result,the patient is exposed to a conspicuous amount of radiation. In contrastto such conventional methods, scanning with radiological imaging device1 can be performed with a reduced emission of radiation by virtue of theuse of a detector 32 comprising linear sensors 32 a and 32 c or the flatpanel sensor 32 f functioning as a linear sensor, and continuouslytranslating the detector 32 along the direction of movement 50 a withoutoverlapping any part of the body in the course of a single scan.

Moreover, in the example embodiment where detector 32 comprises twolinear sensors 32 a and 32 c, the presence of the inversion unit 32 emakes it possible to carry out radiological imaging in both slidingdirections of the gantry 30 along the direction of movement 50 a bypermitting inversion of the order of the linear sensors 32 a and 32 c inrelation to the direction 50 a.

Also, by virtue of the radiological imaging device 1, it is possible toperform total body scanning at 360° and along the entire length of thebed 20.

The various embodiments described above have been presented by way ofexample and not limitation. It will be apparent to persons skilled inthe relevant art(s) that various changes in form and detail can be madetherein (e.g., different hardware, communications protocols, materials,shapes and dimensions) without departing from the spirit and scope ofthe present invention. Thus, the present invention should not be limitedby any of the above-described exemplary embodiments, but should bedefined only in accordance with the following claims and theirequivalents.

In addition, it should be understood that the attached drawings, whichhighlight functionality described herein, are presented as illustrativeexamples. The architecture of the present invention is sufficientlyflexible and configurable, such that it can be utilized (and navigated)in ways other than that shown in the drawings.

Further, the purpose of the appended Abstract is to enable the U.S.Patent and Trademark Office and the public generally, and especiallyscientists, engineers, and practitioners in the relevant art(s), who arenot familiar with patent or legal terms and/or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical subject matter disclosed herein. The Abstract is not intendedto be limiting as to the scope of the present invention in any way.

What is claimed:
 1. A method of acquiring a radiological image of atleast part of a patient placed in a gantry, the method comprising:causing a source to emit radiation that passes through the at least partof the patient, the radiation defining a central axis of propagation;receiving the radiation at a detector, and the detector includes atleast one first linear sensor having a first sensitive surface and asecond linear sensor having a second sensitive surface, wherein thesensitive surfaces are partially overlapped along the direction ofmovement; outputting data signals from the detector to a control unit;generating the radiological image, at the control unit, by generating afirst image acquired by the first linear sensor and a second imageacquired by the second linear sensor, and overlapping the first andsecond images in a region where the first and second linear sensorsoverlap.
 2. The method of claim 1, further comprising continuouslytranslating the source and the detector in a direction of movementsubstantially perpendicular to the central axis of propagation using atranslation mechanism that is connected to the source and the detector.3. The method of claim 2, further comprising acquiring an image fromdata signals received continuously from the detector while thetranslation mechanism continuously translates the source emitting theradiation and the detector receiving the radiation, so as to scan the atleast part of the patient.
 4. The method of claim 1, wherein asuperimposition zone of the sensitive surfaces is positionedsubstantially at the central axis of propagation.
 5. The method of claim1, further comprising providing a bed suitable to support the patient,wherein the bed defines an axis of extension.
 6. The method of claim 5,wherein the direction of movement is substantially parallel to the axisof extension.
 7. The method of claim 5, further comprising rotating thesource and the detector in relation to the axis of extension.
 8. Themethod of claim 1, further comprising reducing edge effects byreconstructing, at the control unit, the radiological image by excludinga portion of the first image that overlaps an edge of the first linearsensor.
 9. The method of claim 8, further comprising reducing edgeeffects by reconstructing, at the control unit, the radiological imageby excluding a portion of the second image that overlaps an edge of thesecond linear sensor.
 10. A radiological imaging device comprising: agantry defining an analysis zone in which at least part of a patient isplaced; a source suitable to emit radiation that passes through the atleast part of the patient, the radiation defining a central axis ofpropagation; and a detector suitable to receive the radiation, and thedetector includes at least one first linear sensor having a firstsensitive surface and a second linear sensor having a second sensitivesurface, the first sensitive surface is equal in size to the secondsensitive surface, and in relation to a direction of movement that isperpendicular to the central axis of propagation, the first sensitivesurface overlaps the second sensitive surface so that a fraction of thefirst and second sensitive surfaces to be hit by the radiation is lessthan 30%.
 11. The device of claim 10, wherein and in relation to thedirection of movement, the first sensitive surface overlaps the secondsensitive surface so that a fraction of the first and second sensitivesurfaces to be hit by the radiation is less than 20%.
 12. The device ofclaim 10, wherein and in relation to the direction of movement, thefirst sensitive surface overlaps the second sensitive surface so that afraction of the first and second sensitive surfaces to be hit by theradiation is less than 10%.
 13. The device of claim 10, furthercomprising a translation mechanism adapted to translate the source andthe detector in the direction of movement substantially perpendicular tothe central axis of propagation.
 14. The device of claim 13, furthercomprising a control unit adapted to acquire an image from data signalsreceived continuously from the detector while the translation mechanismcontinuously translates the source emitting the radiation and thedetector receiving the radiation, so as to scan the at least part of thepatient.
 15. The device of claim 10, wherein the detector includes aninversion unit adapted to rotate at least one of the first linear sensorand the second linear sensor.
 16. The device of claim 15, wherein theinversion unit rotates at least one of the first linear sensor and thesecond linear sensor in relation to an axis of rotation substantiallyparallel to the central axis of propagation.